About

Caroline Strömberg is a professor in the Department of Biology at the University of Washington, with research interests spanning ecology, evolution, systematics, natural history, paleobiology, and plant biology. Her work focuses on the evolution of grasses and the assembly of grassland ecosystems, investigating when and where Poaceae originated and diversified, and how grasses have responded to environmental changes over time. She documents the evolutionary history of Poaceae and grassland ecosystems across multiple regions on different continents to understand the factors shaping the grassy biome. Her research also explores biotic responses to climate change in deep time, examining how plants and animals have responded to major environmental shifts such as changes in climate, atmospheric CO2 levels, and disturbance regimes. She studies the role of plants in faunal responses during environmental change and how ecosystem history influences vegetation responses. Additionally, her work investigates the evolution and functional role of silica in land plants, reconstructing phylogenetic patterns of silica accumulation and phytolith shape in modern and fossil plants. Strömberg's research extends to the ecological and evolutionary dynamics of plant communities during the Late Cretaceous-Paleocene, particularly focusing on the rise of angiosperms and their ecological roles before they became dominant. Her contributions include understanding the origins of C4 grasslands, the spread of grass-dominated habitats, and the responses of ecosystems to past climate events, providing insights into long-term ecological and evolutionary processes.

Research topics

• Ecology
• Geography
• Biology
• Paleontology
• Oceanography
• Environmental science
• Geology
• Computer Science
• Chemistry
• Physical geography
• World Wide Web
• Library science
• Geochemistry
• Climatology
• Agroforestry

Selected publications

• Revisiting the Paleoclimate, Paleoecology, and Age of the Middle Miocene Nyakach Formation, Western Kenya

  SSRN Electronic Journal · 2026-01-01

  preprintOpen access
  PublisherDOI

• The PteridoPortal: A publicly accessible collection of over three million records of extant and extinct pteridophytes

  UNC Libraries · 2026-03-10

  articleOpen access

  Premise: Pteridophytes—vascular land plants that disperse by spores—are a powerful system for studying plant evolution, particularly with respect to the impact of abiotic factors on evolutionary trajectories through deep time. However, our ability to use pteridophytes to investigate such questions—or to capitalize on the ecological and conservation‐related applications of the group—has been impaired by the relative isolation of the neo‐ and paleobotanical research communities and by the absence of large‐scale biodiversity data sources. Methods: Here we present the Pteridophyte Collections Consortium (PCC), an interdisciplinary community uniting neo‐ and paleobotanists, and the associated PteridoPortal, a publicly accessible online portal that serves over three million pteridophyte records, including herbarium specimens, paleontological museum specimens, and iNaturalist observations. We demonstrate the utility of the PteridoPortal through discussion of three example PteridoPortal‐enabled research projects. Results: The data within the PteridoPortal are global in scope and are queryable in a flexible manner. The PteridoPortal contains a taxonomic thesaurus (a digital version of a Linnaean classification) that includes both extant and extinct pteridophytes in a common phylogenetic framework. The PteridoPortal allows applications such as greatly accelerated classic floristics, entirely new “next‐generation” floristic approaches, and the study of environmentally mediated evolution of functional morphology across deep time. Discussion: The PCC and PteridoPortal provide a comprehensive resource enabling novel research into plant evolution, ecology, and conservation across deep time, facilitating rapid floristic analyses and other biodiversity‐related investigations, and providing new opportunities for education and community engagement.

  PublisherDOI

• Neotropical terrestrial records indicate colder, more densely vegetated lowland landscapes between the middle and late Miocene

  Palaeogeography Palaeoclimatology Palaeoecology · 2026-04-19

  articleSenior author
  PublisherDOI

• Revisiting the paleoclimate, paleoecology, and age of the Middle Miocene Nyakach Formation, Western Kenya

  Palaeogeography Palaeoclimatology Palaeoecology · 2026-05-12

  article
  PublisherDOI

• Deep learning approaches to the phylogenetic placement and classification of fossil grass silica short cell phytoliths

  Abstracts with programs - Geological Society of America · 2025-01-01

  articleSenior author
  PublisherDOI

• African C3 grass n-alkane distributions & plant chemotaxonomy

  Organic Geochemistry · 2025-04-06 · 1 citations

  articleOpen access

  • Existing proxies are ill-suited to reconstruct grassy African C 3 ecosystems. • C 3 PACMAD grasses produce exceptionally high abundances of long-chain n- alkanes, and thus measuring and reporting the C 35 n -alkane is important. • C 3 grass n -alkane distributions are influenced by both phylogeny and physiology. • n -Alkane distributions are a potential C 3 grass paleoproxy in sedimentary archives. Reconstructing past vegetation can elucidate the timing, climate forcings, and biotic mechanisms of ecosystem change. Plant macro- and microfossils are traditionally used to study past vegetation but suffer from production and taphonomic biases, such as underrepresentation of important herbaceous vegetation components. Geochemical proxies can fill this gap, but carbon isotopes (δ 13 C) in isolation are unable to distinguish between structurally different C 3 habitats, such as forests and grasslands. Thus, new geochemical methods to identify grassy C 3 ecosystems are necessary. We present n -alkane chain length distributions of 209 plant specimens from two Kenyan C 3 -dominated ecosystems, representing a wide range of plant functional types (PFTs). We find that C 3 PACMAD grasses produce exceptionally high abundances of long chain C 33 and C 35 n -alkanes (ACL = 32.7, mean C 33 + C 35 relative abundance = 0.69), unlike other C 3 PFTs which produce low abundances of C 33 and C 35 (ACL = 28.9–30.3, mean C 33 + C 35 relative abundance = 0.0–0.21). This finding highlights the importance of measuring and reporting the C 35 n -alkane. Our data further demonstrate that n -alkane distributions can serve as a proxy for some African C 3 PACMAD grasses, offering a new paleoecological tool for distinguishing C 3 vegetation types.

  PublisherDOI

• Estimating carbon assimilation rates from fossil leaves and application to the mid‐Miocene Clarkia forest

  American Journal of Botany · 2025-08-01

  articleOpen accessSenior author

  Abstract Premise The rate of carbon assimilation in leaves ( A ) is a key trait central to a plant's economic strategy that has downstream impacts on the regional and global cycling of carbon and other nutrients. Most previous paleoecological studies estimate A from nearest living relatives or leaf vein density. Methods We present a method for reconstructing A using gas‐exchange modeling that requires both measured (stomatal size and density, leaf δ 13 C) and inferred (e.g., atmospheric CO 2 concentration) inputs. We apply this method to ten extant taxa and nine fossil taxa representing common angiosperms of the exquisitely preserved mid‐Miocene (~15.9 Ma) flora at Clarkia in northern Idaho, USA. Results Application to extant taxa produces estimates of A that are near measured values on the same leaves (R 2 = 0.89 across all taxa). Median reconstructed A for fossil taxa range from 9.5–21.7 µmol m –2 s –1 with 95% confidence intervals ~+51%/–38% indicating that most species are statistically indistinguishable. Sensitivity tests show that our method is most reliable when CO 2 is well‐constrained, but when that is impractical, taxa within single sampling horizons (with a presumed fixed CO 2 concentration) can be organized by A into a relative rank order with tighter confidence intervals (~+16%/–14%). Conclusions Following this relative approach at Clarkia, we reconstruct high A for taxa whose modern relatives are characterized by rapid growth and/or riparian habitats ( Castanea and Platanus ) and corroborate previous interpretations on the ecology of taxa whose modern relatives are less known ( Quercus simulata ).

  PublisherOA PDFDOI

• Using Grass Phytolith 3-D Morphology to Reconstruct the Evolution of Grasses

  Abstracts with programs - Geological Society of America · 2025-01-01

  articleSenior author
  PublisherDOI

• 3-D Morphology Of Fossil Phytoliths Shows That The Earliest Grasslands Of North America And Western Eurasia Were Dominated By Cold-Season Grasses

  Abstracts with programs - Geological Society of America · 2025-01-01

  article1st authorCorresponding
  PublisherDOI

• The PteridoPortal: A publicly accessible collection of over three million records of extant and extinct pteridophytes

  Open MIND · 2025-01-01

  article

  Premise: Pteridophytes—vascular land plants that disperse by spores—are a powerful system for studying plant evolution, particularly with respect to the impact of abiotic factors on evolutionary trajectories through deep time. However, our ability to use pteridophytes to investigate such questions—or to capitalize on the ecological and conservation‐related applications of the group—has been impaired by the relative isolation of the neo‐ and paleobotanical research communities and by the absence of large‐scale biodiversity data sources. Methods: Here we present the Pteridophyte Collections Consortium (PCC), an interdisciplinary community uniting neo‐ and paleobotanists, and the associated PteridoPortal, a publicly accessible online portal that serves over three million pteridophyte records, including herbarium specimens, paleontological museum specimens, and iNaturalist observations. We demonstrate the utility of the PteridoPortal through discussion of three example PteridoPortal‐enabled research projects. Results: The data within the PteridoPortal are global in scope and are queryable in a flexible manner. The PteridoPortal contains a taxonomic thesaurus (a digital version of a Linnaean classification) that includes both extant and extinct pteridophytes in a common phylogenetic framework. The PteridoPortal allows applications such as greatly accelerated classic floristics, entirely new “next‐generation” floristic approaches, and the study of environmentally mediated evolution of functional morphology across deep time. Discussion: The PCC and PteridoPortal provide a comprehensive resource enabling novel research into plant evolution, ecology, and conservation across deep time, facilitating rapid floristic analyses and other biodiversity‐related investigations, and providing new opportunities for education and community engagement.

Frequent coauthors

• Colin P. Osborne

  University of Sheffield

  63 shared

• Erika J. Edwards

  Yale University

  59 shared

• Nicolas Salamin

  University of Lausanne

  55 shared

• Elizabeth L. Spriggs

  U.S. National Arboretum

  51 shared

• Pascal‐Antoine Christin

  University of Sheffield

  51 shared

• Alice Novello

  Centre de Recherche et d’Enseignement de Géosciences de l’Environnement

  40 shared

• Regan E. Dunn

  Natural History Museum of Los Angeles County

  33 shared

• Matthew J. Kohn

  30 shared

Education

• B.A.

  Lund University

• M.S.

  Lund University

• Ph.D., Department of Integrative Biology

  University of California, Berkeley

Awards & honors

• 2007 Postdoctoral Fellow, National Museum of Natural History…
• 2004-2006 Postdoctoral Fellow, Swedish Museum of Natural His…